Some of my clients do it as a standard practice - and they do not suffer in their Google traffic. With today's evolution toward a more visual and less verbal audience, it seems important in many markets.

Whether or not it helps you rank would depend on how your users react to it. I worked in the travel vertical for many years. Images were great for retaining the aspirational travel searcher (those who hadn't decided where to go and needed some eye candy to make up their mind). We found that folks who were ready to buy and were price checking on search engines were more interested in quick access to deals. Expensive looking images actually turned some of them away.

Much of ranking is giving the searcher what they want so they don't bounce back to the the SERPs and look at your competitor.